The durability of synthetic valve leaflets is partially a function of the character of bending by the leaflet during the opening-closing cycle. Small radius bends, creases and intersecting creases, can produce high stress zones in the leaflet. These high stress zones can cause the formation of holes and tears under repetitive loading.
Prosthetic valves may be delivered using surgical or transcatheter techniques. A surgical valve is implanted into a patient using open-heart surgical techniques. The surgical valve is usually manufactured to have a fixed diameter as opposed to a transcatheter valve which is required to attain a range of diameters for access and delivery. The surgical valve is usually provided with a sewing cuff about a perimeter of the valve to allow for suturing to the native tissue orifice. Sewing cuffs are well known in the art.
In addition to the valve durability issues discussed above, the transcatheter valve must also be able to withstand the handling and deployment stresses associated with being compressed and expanded
The shape most often described as preferable is modeled after the native human aortic valve. Though nature dictates the optimum shape for the native tissues to form a heart valve, we have discovered this is not true for synthetic materials; accordingly, the design specified in the current disclosure is instead intended to place the synthetic material under a minimized stress condition as compared to those based on copies of the native valve. This is partially accomplished through reduced buckling in the leaflet material.
There exists a need for a durable synthetic prosthetic valve that may be delivered either surgically or endovascularly.